2013-07-25

lensing cross-correlations, Gaussian Processes

In Galaxy Coffee, Myers (Wyoming) talked about cross-correlations of quasars with the CMB convergence (lensing) map. There are now large-scale convergence maps available, so it is possible to more-or-less automatically generate object-lensing cross-correlations. These are pretty straightforwardly interpretable in terms of halo occupation or mass correlations. This is a great new capability for cosmology, and permits testing of a lot of halo-occupation ideas that have been kicking around for a few years.

In the afternoon, Foreman-Mackey talked about our work with Kepler. He made various important points, but what I learned most clearly is that the biggest advantage we gain over our competitors by using Gaussian Processes is in what we call "search": We can do hypothesis tests or parameter estimation quickly but still marginalize out the stochastic variations of the stars.